The LED technology is commonly applied in the illumination field. This technology has the advantages such as high efficiency and energy saving, and especially the flexible lighting strip using the LED technology not only has the advantages of the LED technology but also can be applied to various outdoor circumstances utilizing its characteristics such as flexibility and sealing performance. The conventional LED flexible lighting strip achieves full-sealing of the light source and achieves the waterproof and dustproof effects, but owing to the design limitation thereof, the requirements of the users to the color temperature of the light of the lighting strip cannot be met. Users usually expect that the light of the lighting strip can have warm white color temperature, but the existing flexible lighting strip generally directly encapsulates the light source completely with flexible material, and the encapsulation material is closely in contact with the light source. The color temperature of such type of product often only has a color temperature biased to cold light due to the encapsulation result, and a sealed lighting strip with a warm color temperature cannot be achieved. Besides, apart from a cold color temperature, such conventional lighting strip does not have a lumen output high enough and cannot achieve sufficient illumination strength.